Conventionally, it is known that an effect such as antireflection effect and antiglare effect are exhibited by formation of irregularities in the surface of a glass plate. In particular, there is known a technique of appropriately controlling the size, depth, pitch or the like of the concave portion to decrease the reflectance on the glass plate surface and thereby enhance the antiglare effect or to obtain an effect of increasing the wettability of immersion solution when forming a film on the glass surface by a dip-coating treatment. Also, it is known that when the size or the like of the concave portion is appropriately controlled, an effect of increasing the wettability to a glass fiber resin at the production of a glass fiber-reinforced plastic or controlling the light transmittance of architectural glass is exhibited. Furthermore, when a water-repellent film is formed after providing irregularities in the surface of a vehicle windshield, an effect of increasing durability of the water-repellent film against sliding friction with a rainwater wiper or the like thereby enhancing adherence of the water-repellent film to the windshield is also known.
The dimension such as size, depth and pitch of the concave portion on the glass surface is supposed to be adjustable in the range from several nm to several tens of μm by the production method. For example, Patent Documents 1 to 5 disclose a method of roughening a quartz glass substrate surface by a blasting method and then applying an etching treatment with an aqueous hydrofluoric acid solution to produce a quartz glass substrate having a semispherical dimple of 0.5 to 5 μm in diameter (Patent Document 1); a method of treating a glass surface with a glass surface-treating solution containing hydrogen fluoride to form an uneven surface having a surface roughness Ra of 0.1 to 2 μm and a surface roughness Rmax of 1 to 20 μm (Patent Document 2); a method of subjecting a glass substrate surface to a texturing treatment and then to a scrubbing treatment using a predetermined sponge to produce a glass substrate for image recording mediums (Patent Document 3); a method of precisely polishing a glass substrate surface with an abrasive containing a free abrasive grain and further applying a surface treatment with a hydrofluorosilicic acid to produce a glass substrate for magnetic recording mediums (Patent Document 4); and a method of reacting a sulfurous acid gas, an anhydrous sulfuric acid gas or a chlorine gas with a glass surface under heating to produce an SiO2-rich layer on the glass surface and forming a hole of approximately from 1 to 5 μm by utilizing a thermal expansion difference between the SiO2-rich layer and the glass base material at the subsequent reheating time (Patent Document 5).    Patent Document 1: JP-A-2000-223724    Patent Document 2: JP-A-2001-335342    Patent Document 3: JP-A-2002-352422    Patent Document 4: JP-A-2000-348344    Patent Document 5: JP-A-2000-72491